// var obj1 = {x: 100}
// var obj2 = obj1
// obj2['x'] = 200
// console.log(obj1.x)


var obj1 = { x: 100 }
var obj2 = obj1
obj1.y = obj1 = { x: 200 }
// 先执行obj1.y = {x:200}
console.log(obj1.y)
console.log(obj2)
